Return bend fitting



y 24, 1932- R. STEWART 1,859,850

RETURN BEND FITTING Filed Dec, 4, 1930 2 Sheets-Sheet l INVENTOR BY 4 MM,

ATTORNEYS EL. Jzewarf RETURN BEND FITTING Filed Dec. 4, 1930 2 Sheets-Sheet 2 ATTORNEYS Patented May 24, 1932' UNITED STATES PATENT OFFICE ROY L. STEWART, OF IBTBMING, ALABAMA, ASSIGNOR T FRED C. FANTZ, 0F

WEBSTER GROVES, MISSOURI RETURN BEND FITTING Application filed December 4, 1930. Serial No. 500,114. 7

This invention relates to fittings for the tubes of oil stills and, among other objects, aims to provide an improved return bend or header assembly of the type wherein the ends of the tubes are adapted to be expanded into yoke members which clamp the bend in place.

Another aim of the -invention is to provide an improved joint between the ends'of the return bend or header and the base or outer "face to of the yoke members so that the bend may be applied and removed very quickly and will not stick due to carbon or coke deposits. The

main idea is to provide a very strong, durable and relatively cheap fitting of the rolled-in it type that can be made of steel or suitable alloys and applied to plain steel or alloy tubes, without requiring any special machine operations on the tubes or complex jigging operations to insure tight joints.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawings, wherein Fig. l is a plan view of one form of return bend fitting or assembly embodying the invention;

Fig. 2 is a side elevation, partly in section, of the fitting shown in Fig. l

Fig. 3 is a side elevation taken at right angles to Fig. 2;

Fig. 4 is a fragmentary elevation, partly in section, showing a wing-type toggle for clamping the bend on its seat; and

Fig. 5 is a fragmentary sectional view showing a slightly modified form of fitting.

Many of the modern oil stills which operate at relatively high pressures and temperatures, have special alloy tubes which are exposed to radiant heat in the furnace. The fittings or return bend connections for such tubes are sometimes made of the same alloy so that they will withstand high temperatures and pressures and resist corrosion and erosion. Since the tubes in the lower bank or radiant heat zone frequently have to be turned or removed for repairs and/or replaced, it is desirable to employ return bend fittings of the type shown in U. 55. Patent 1,752,331 to Fred C. Fantz' so that the tubes can easily and quickly be removed from the yokes. In some instances, less expensive carbon steel tubes are used in the upper banks and also in the lower banks, especially when the pressures are not prohibitively high. Inasmuch as carbon steel tubes can be replaced '55 without excessive cost, some oil companies prefer to employ rolled-in steel fittings because they are also much less expensive than alloy fittings. In fact, some stills utilize steel fittings on alloy tubes. This invention, therefore, aims to provide an improved fitting of this character that is very strong and durable and that can easily be applied in the field to ordinary plain-end tubes.

Referring particularly to the drawings, one example of a fitting embodying the invention is. shown in Figs. 1 and 2. In this instance, a yoke having a tube engaging portion 10 and integral side walls 11 is provided with spaced tube openings into which two parallel tubes 12 are expanded as shown in Fig. 2. The side walls 11 are so spaced as to permit the insertion and removal of a return bend 13 of approximately the same internal diameter as the internal diameter of the tubes. Hence, an ordinary tube expander, not shown, can be inserted between them.

In the example illustrated in Figs. 1 and 2, the tubes 12 are inserted through the tube-engaging portion 10 and their extreme ends are flared outwardly. Tn fact, the ends may project slightly beyond the outer face of the tube-engaging portion 10 and it is not necessary'to use any jig during the expanding 0peration. $5

Referring to Fig. 2, the outer face of the tube-engaging portion 10 is shown as having annular, ti-shaped grooves 14c which are concentric with the tube openings and tubes and constitute seats for annular beads or tongues 15 machined or formed on the ends of the return bend adjacent to the outer peripheral edges. The arrangement is such that the return bend will never stick due to an accumulation of coke or carbon on the inside of the joint between the ends of the tubes and the ends of the bend. This small annular space will very quickly coke up so that the conduit is practically continuous and the joint is protected to some extent by the coke. Also, the m space permits tightening of the joints after the parts wear. Moreover, the grooved seats in the face of the base are not easily damaged by tube reamers or the ordinary tools used at frequent intervals for cleaning the tubes.

The side walls 11 extend beyond the return bend and are here shown as having diametrically opposed, longitudinal slots or openings 16 to receive the arms or wings 17 of removable bars or toggles 18 carrying large set screws 19. In Figs. 2 and 4, the outer ends of the slots 16 and the engaging edgesof the arms 17 are shown as being arcuate so that the arms will automatically center themselves in the slots. The ends of the set screws are rounded as usual and are adapted to be seated in recesses or depressions 20 on bosses 21 which are formed on the return bend. The arrangement is such that the set screws center themselves and apply the pressure axially of each bend opening. Further, the wing toggles can be easily and quickly applied and removed.

In some instances it is desirable to connect the side walls 11 to prevent them from spreading laterally or separating due to the clamping pressure. This is necessary when ordinary toggles are employed. The walls 11 are shown as being connected by arcuate portions 22 at the opposite ends of the yoke as shown so that they are more or less crescent-shaped at their outer ends. The arcuate portions 22 are preferably of the same thickness as the walls and may be of any desired width, although it is not necessary that they extend to the tube-engaging portion. Thus,,the weight of the yoke is kept down I to a minimum, consistent with adequate strength.

The modified form of return bend fitting shown in Fig. 5 difiers from the one hereinbefore described in that the tube-engaging portion 10' of the yoke is made much thicker and has counterbored sockets S into which the ends of the tubes are expanded. The openings beyond the ends of the tubes are preferably of the same internal diameter as the internal diameter of the tubes. In this example, the grooved seats 14' in the outer face of the tube-engaging portion may be of less diameter than they are in the first form. Moreover, this design is such that the inner sides of the grooved seats cannot be swaged by the tube roller or expander in case the expanding operation is overdone. Further, the ends of the bend can be made somewhat smaller, thereby permitting the side walls 11 to be made relatively thick without increasing the width of the yoke.

When the distance between centers of the tubes is relatively small, the modified form shall be applied principally to steel tubes.

Hence, the relatively inexpensive steel yokes will be satisfactory. It will be understood that yokes embodying this invention may be employed to secure bends or couplings of different shapes to the ends of tubes. For example, several yoke members may be combined or they may be separate and used to clamp multiple bends, elbows and couplings of other shapes.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shown and described. More over, it is not indispensable that all the features of the invention be used conjointly, since they may be employed advantageously in various combinations and sub-combinations.

What is claimed is 1 1-. In a refinery apparatus, means for connecting a conventional return bend to a pair of still tubes comprising, a housing member having substantially-circular openings therein, the walls of which are provided .with cir-.

cumferential recesses adapted to interlock with the walls of the pair of tubes when they are rolled into said recesses, an annular ridge on each face of said return bend, there being an annular recess in said housing surrounding each tube'adapted to receive said ridge, and means carried by the housing for holding said return bend and housing in assembled relation to form a gas-tight jolnt.

2. In a refinery apparatus, means for connecting a conventional return bend to a pair of still tubes, comprising, a housing member having substantially circular openings therein, the walls of which are provided with circumferential recesses adapted to interlock with the walls of the pair of tubes when they arerolled into said recesses, an annular ridge substantially convex in cross section on each face of said return bend, there being an annular recess substantially V'-shaped in cross section in said housing surrounding each tube adapted to receive said ridge, and means carried by the housing for holding said return bend and housing in assembled relation to form a gas-tight joint.

3. In a refinery apparatus, means for connecting the conventional return bend to a pair of still tubes, comprising a housing member having substantially circular openings therein, the walls of which are provided with recesses adapted to interlock with the walls of said tubes when they are rolled into said recesses, means forming a leak-proof joint between the return bend and the housing concentric with the tubes, comprising a groove on one member and a rib on the other,

and means for holding said return bend and housing in assembled relation to forma gastight joint.

4. In a refinery apparatus, means for connecting the conventional return bend to a pairof still tubes, comprising a housing member having substantially circular openings therein, the walls of Which are provided with recesses adapted to interlock with the walls of said tubes when they are rolled into said recesses, means forming a leak-proof joint between the return bend and the housing spaced from but concentric with the tubes, comprising a groove on one member and a rib 011 the other, and means for hold ing said return bend and housing in assem bled relation to form a gas-tight joint.

5. In a refinery apparatus, means for connecting the conventional return bend to a pair of still tubes, comprising a housing member having substantially circular openings therein, the walls of which are provided with recesses adapted to interlock with the walls of said tubes when they are rolled into said recesses, means forming a leak-proof joint between the return bend and the housing spaced from but concentric with the tubes,

comprising mating members on said housing and said return bend, and means for holding said return bend and housing in assembled relation to form a gas-tight joint.

In testimony, that I claim the foregoing as my own, I have hereto aflixed my signature.

ROY L. STEWART. 

